Limerick is Ireland's fourth largest city, after Dublin, Belfast and Cork, and the third largest in the Republic. It is also the name of the surrounding county. I come from there. It's not terribly exciting, but is the home of rugby in Ireland. Part of the province of Munster.
Located on the estuary of the Shannon river, the city was originally a Viking settlement, established in the ninth century. In the tenth century, it was seized by Mahon, the Irish King of Thomond, and his brother Brian Boru. Brian later became High King of all Ireland, and his descendents the O'Briens ruled Limerick for 200 years, until the arrival of the Normans, who seized the walled city in 1194. King John built an impressive castle on what is now known as King's Island, around which the Anglo-Norman settlement, or Englishtown, was established. The native inhabitants were moved to the other side of the Abbey River, or Irishtown. At around the same time (early 13th century), King John granted Limerick its charter as a city, and the surrounding area was established as the county of Limerick.